140 research outputs found

    No impact of nitrogen fertilization on carbon sequestration in a temperate Pinus densiflora forest

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    Carbon (C) sequestration capacity in forest ecosystems is generally constrained by soil nitrogen (N) availability. Consequently, N fertilization is seen as a promising tool for enhancing ecosystem-level C sequestration in N-limited forests. We examined the responses of ecosystem C (vegetation and soil) and soil N dynamics to 3 years of annual nitrogen-phosphorus-potassium (N3P4K1 = 11.3 g N, 15.0 g P, 3.7 g K m−2 year−1) or PK fertilization (P4K1), observed over 4 years in a 40-year-old Pinus densiflora forest with poor N nutrition in South Korea. PK fertilization without N was performed to test for PK limitation other than N. Neither tree growth nor soil C fluxes responded to annual NPK or PK fertilization despite an increase in soil mineral N fluxes following NPK fertilization. NPK fertilization increased the rate of N immobilization and 80% of the added N was recovered from mineral soil in the 0–5 cm layer, suggesting that relatively little of the added N was available to trees. These results indicate that N fertilization does not always enhance C sequestration even in forests with poor N nutrition and should therefore be applied with caution

    Quetiapine Misuse and Abuse: Is It an Atypical Paradigm of Drug Seeking Behavior?

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    Recent case reports in medical literatures suggest that more and more second-generation atypical antipsychotics (AAs) have been prescribed for off-label use; quetiapine (Brand name: SeroquelÂź) showed increase in its trend for off-label use. Little is known about the reasons behind this trend, although historical sedative and hypnotic prescription patterns suggest that despite relatively superior safety profiles of quetiapine (especially for movement disorders), it may be used for treating substance abuse disorder. In addition, recent studies have shown a strong potential for misuse and abuse (MUA) of quetiapine beyond Food and Drug Administration-approved indications. This includes drug-seeking behaviors, such as feigning symptoms, motivated by quetiapine and use of quetiapine in conjunction with alcohol. Quetiapine appears to be the most documented AA with street values bartered illicitly on the street. A recent report from the Drug Abuse Warning Network has shown a high prevalence of quetiapine-related emergency department visits involving MUA. Several other case studies have found that quetiapine causes seeking behaviors observed in substance use disorder. In fact, the majority of quetiapine MUA involved patients diagnosed with substance use disorder. In the absence of a definitive mechanism of action of quetiapine\u27s reinforcing properties, it is imperative to gather robust evidence to support or refute increasing off-label use of AAs

    A study of the anti-inflammatory effects of the ethyl acetate fraction of the methanol extract of Forsythiae fructus

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    Background: The dried fruit of Forsythia suspensa (Thunb.) Vahl. (Oleaceae) are better known by their herbal name Forsythiae Fructus, and have a bitter taste, slightly pungent smell, and cold habit. FF has been widely used to treat symptoms associated with the lung, heart, and small intestine. Recently, bioactive compounds isolated from hydrophobic solvent fractions of FF have been reported to have anti-oxidant, anti-bacterial, and anti-cancer effects. Traditionally, almost all herbal medicines are water extracts, and thus, extraction methods should be developed to optimize the practical efficacies of herbal medicines.Materials and Methods: In this study, the anti-inflammatory effects of the ethyl acetate fraction of the methanol extract of FF (FFE) were assessed by measuring NO and PGE2 production by and intracellular ROS and protein levels of iNOS and COX-2 in RAW 264.7 cells.Results: FFE inhibited COX-2 expression in LPS-stimulated RAW 264.7 cells.Conclusion: In summary, FFE effectively reduced intracellular ROS and NO levels and inhibited PGE2 production by downregulating COX-2 levels.Keywords: Forsythiae Fructus, herb, inflammation, efficacy

    Performance of a Distributed Simultaneous Strain and Temperature Sensor Based on a Fabry-Perot Laser Diode and a Dual-Stage FBG Optical Demultiplexer

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    A simultaneous strain and temperature measurement method using a Fabry-Perot laser diode (FP-LD) and a dual-stage fiber Bragg grating (FBG) optical demultiplexer was applied to a distributed sensor system based on Brillouin optical time domain reflectometry (BOTDR). By using a Kalman filter, we improved the performance of the FP-LD based OTDR, and decreased the noise using the dual-stage FBG optical demultiplexer. Applying the two developed components to the BOTDR system and using a temperature compensating algorithm, we successfully demonstrated the simultaneous measurement of strain and temperature distributions under various experimental conditions. The observed errors in the temperature and strain measured using the developed sensing system were 0.6 °C and 50 ΌΔ, and the spatial resolution was 1 m, respectively

    A STUDY OF THE ANTI-INFLAMMATORY EFFECTS OF THE ETHYL ACETATE FRACTION OF THE METHANOL EXTRACT OF FORSYTHIAE FRUCTUS

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    Background: The dried fruit of Forsythia suspensa (Thunb.) Vahl. (Oleaceae) are better known by their herbal name Forsythiae Fructus, and have a bitter taste, slightly pungent smell, and cold habit. FF has been widely used to treat symptoms associated with the lung, heart, and small intestine. Recently, bioactive compounds isolated from hydrophobic solvent fractions of FF have been reported to have anti-oxidant, anti-bacterial, and anti-cancer effects. Traditionally, almost all herbal medicines are water extracts, and thus, extraction methods should be developed to optimize the practical efficacies of herbal medicines. Materials and Methods: In this study, the anti-inflammatory effects of the ethyl acetate fraction of the methanol extract of FF (FFE) were assessed by measuring NO and PGE2 production byand intracellular ROS and protein levels of iNOS and COX-2in RAW 264.7 cells. Results: FFE inhibited COX-2 expression in LPS-stimulated RAW 264.7 cells. Conclusion: In summary, FFE effectively reduced intracellular ROS and NO levels and inhibited PGE2 production by down- regulating COX-2 levels

    The Development of Transparent Photovoltaics

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    Transparent photovoltaics (TPVs), which combine visible transparency and solar energy conversion, are being developed for applications in which conventional opaque solar cells are unlikely to be feasible, such as windows of buildings or vehicles. In this paper, we review recent progress in TPVs along with strategies that enable the transparency of conventional photovoltaics, including thin-film technology, selective light-transmission technology, and luminescent solar concentrator technology. From fundamental research to commercialization of the TPV, three main perspectives should be considered: (1) high-power conversion efficiency at the same average visible transmittance; (2) aesthetic factors, which should not detract from applications such as buildings and vehicles; and (3) feasibility for real-world applications, including modularization and stability evaluation. We present the distinct analysis criteria for these main perspectives and discuss their importance. We also discuss possible research directions for the commercialization of TPVs

    Single-cell transcriptome of the mouse retinal pigment epithelium in response to a low-dose of doxorubicin

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    Single cell transcriptomics pinpoints a cell subpopulation that could be involved in inducing cellular senescence of the retinal pigment epithelium, which in turn may construe retinal degenerative disease. Cellular senescence of the retinal pigment epithelium (RPE) is thought to play an important role in vision-threatening retinal degenerative diseases, such as age-related macular degeneration (AMD). However, the single-cell RNA profiles of control RPE tissue and RPE tissue exhibiting cellular senescence are not well known. We have analyzed the single-cell transcriptomes of control mice and mice with low-dose doxorubicin (Dox)-induced RPE senescence (Dox-RPE). Our results have identified 4 main subpopulations in the control RPE that exhibit heterogeneous biological activities and play roles in ATP synthesis, cell mobility/differentiation, mRNA processing, and catalytic activity. In Dox-RPE mice, cellular senescence mainly occurs in the specific cluster, which has been characterized by catalytic activity in the control RPE. Furthermore, in the Dox-RPE mice, 6 genes that have not previously been associated with senescence also show altered expression in 4 clusters. Our results might serve as a useful reference for the study of control and senescent RPE

    Cooperative evolution of polar distortion and nonpolar rotation of oxygen octahedra in oxide heterostructures

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    Polarity discontinuity across LaAlO3/SrTiO3 (LAO/STO) heterostructures induces electronic reconstruction involving the formation of two-dimensional electron gas (2DEG) and structural distortions characterized by antiferrodistortive (AFD) rotation and ferroelectric (FE) distortion. We show that AFD and FE modes are cooperatively coupled in LAO/STO (111) heterostructures; they coexist below the critical thickness (t(c)) and disappear simultaneously above tc with the formation of 2DEG. Electron energy-loss spectroscopy and density functional theory (DFT) calculations provide direct evidence of oxygen vacancy (VO) formation at the LAO (111) surface, which acts as the source of 2DEG. Tracing the AFD rotation and FE distortion of LAO reveals that their evolution is strongly correlated with VO distribution. The present study demonstrates that AFD and FE modes in oxide heterostructures emerge as a consequence of interplay between misfit strain and polar field, and further that their combination can be tuned to competitive or cooperative coupling by changing the interface orientation
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